When an individual suffers a puncture wound to the chest, such as from being shot or stabbed, the wound often penetrates into the chest cavity so as to puncture the parietal pleura, visceral pleura, and sometimes even the lungs. Such a wound allows air to flow freely into the chest cavity and pleural space.
An open pneumothorax is a condition wherein air penetrates into the pleural space between the lung(s) and the chest wall through a wound hole. When a patient has an open pneumothorax, the normal mechanism by which the lungs expand is inhibited or lost. Consequently, the affected lung will not expand when the patient inhales and respiratory distress ensues. The severity of an open pneumothorax can be minimized by sealing the open wound. However, already trapped air is not allowed to escape from the pleural space.
U.S. Pat. No. 5,478,333 discloses a chest seal having a duck bill valve that prevents air from entering the pleural space while allowing already trapped air to escape. The duck bill valve is attached to a cylindrical section of duct that projects from the body attached flange of the chest seal. The cylindrical section allows the chest seal to be used as a conduit for a catheter if a severe tension pneumothorax or collapsed lung is to be treated with an invasive procedure and/or allows a suction device to be inserted if a hemothorax or collapsed lung is to be treated without invasive procedures. However, the cylindrical section and elongated duck bill valve are obtrusive. The dangling free end of the valve may be inadvertently caught and pulled by medical personnel or equipment so as to dislodge the chest seal and/or pressure from medical equipment or other dressings may prevent the duck bill valve from venting the chest wound. In fact the '333 patent explains that the one-way valve may not open to allow air to be expelled if the patient is lying on the valve.
Thus, a need remains for a low profile chest seal that ensures effective venting of the pleural cavity while sealing a chest wound against air entry, without risk of being dislodged during treatment of the patient, particularly when invasive procedures or other auxiliary procedures are not required.